1. Field of the Invention
The present invention relates to a display unit that displays images by controlling multiple light-emitting devices included in each pixel using video signals.
2. Description of the Related Art
In a color display unit that includes an array of light-emitting devices, such as LEDs (light-emitting diodes), and makes fine display by driving the light-emitting devices individually, the luminance and chromaticity vary among the pixels due to such as manufacturing variations in the light-emitting devices even if same video signals are inputted into the light-emitting devices. As a result, the image quality is reduced. For this reason, there has been presented a method of correcting signals to be inputted into the light-emitting devices by performing 3×3-matrix operations on the video signals, as disposed in Japanese Unexamined Patent Application Publication Nos. 2000-155548 and 2001-188513.
The above-mentioned method will be described briefly. In one pixel, video input signal Ri, Gi, and Bi are converted into signals Ro, Go, and Bo to be inputted into LEDs, by performing matrix operations shown in Formula 1 (Formulas (a) and (b)) described below. By performing such correction, the pixel is displayed with the luminance and chromaticity intended by the video input signals.
                              [                      Formula            ⁢                                                  ⁢            1                    ]                ⁢                                                                                                (                                                    Ro                                                                    Go                                                                    Bo                                              )                =                  M          ⁡                      (                                                            Ri                                                                              Gi                                                                              Bi                                                      )                                              Formula        ⁢                                  ⁢                  (          a          )                                        M        =                                            (                                                                                          Lr                      ⁢                                                                                          ⁢                      1                                                                                                  Lg                      ⁢                                                                                          ⁢                      1                                                                                                  Lb                      ⁢                                                                                          ⁢                      1                                                                                                                                  Lr                      ⁢                                                                                          ⁢                      2                                                                                                  Lg                      ⁢                                                                                          ⁢                      2                                                                                                  Lb                      ⁢                                                                                          ⁢                      2                                                                                                                                  Lr                      ⁢                                                                                          ⁢                      3                                                                                                  Lg                      ⁢                                                                                          ⁢                      3                                                                                                  Lb                      ⁢                                                                                          ⁢                      3                                                                                  )                                      -              1                                ⁢                      (                                                                                Sr                    ⁢                                                                                  ⁢                    1                                                                                        Sg                    ⁢                                                                                  ⁢                    1                                                                                        Sb                    ⁢                                                                                  ⁢                    1                                                                                                                    Sr                    ⁢                                                                                  ⁢                    2                                                                                        Sg                    ⁢                                                                                  ⁢                    2                                                                                        Sb                    ⁢                                                                                  ⁢                    2                                                                                                                    Sr                    ⁢                                                                                  ⁢                    3                                                                                        Sg                    ⁢                                                                                  ⁢                    3                                                                                        Sb                    ⁢                                                                                  ⁢                    3                                                                        )                                              Formula        ⁢                                  ⁢                  (          b          )                    
Lr1, Lr2, and Lr3 in Formula (b) are values determined by measuring the luminances and chromaticities of an R (red) LED of this pixel, Lg1, Lg2, and Lg3 are values determined by measuring the luminance and chromaticity of a G (green) LED of this pixel, and Lb1, Lb2, Lb3 are values determined by measuring the luminance and chromaticity of a B (blue) LED of this pixel, and Sr1, Sr2, Sr3, Sg1, Sg2, Sg3, Sb1, Sb2, and Sb3 are values determined on the basis of the color gamut conceived by these video signals.
In order to obtain a display unit that corrects the luminance and chromaticity using these Formulas, the luminance and chromaticity of R, G, and B of all pixels are measured in advance, a matrix M is obtained with respect to each pixel by performing a calculation, and the obtained matrixes M are stored in a memory or the like. Then, during operation of the display unit, real-time operations are performed on these matrixes M and video signals to obtain LED signals, and display is made by driving the LEDs in accordance with the obtained LED signals.